The openside was capped four times in 2014 and has made 183 appearances for Glasgow Warriors the third most in the club’s history.
He was in the side that won the Guinness Pro12 in season 2014-15, coming off the bench in the final against Munster in Belfast.
Fusaro, 31, has been part of the Glasgow squad for 12 seasons, having made his debut in February 2010 against Cardiff Blues at Firhill.
He announced his retirement on Instagram, with a heartfelt tribute to his wife, team-mates, coaches and the Warriors supporters.
“The years are full of nothing but the best of memories, and it is hard to put into words my gratitude to everyone who has helped me make them,” he said.
“To all my coaches at Glasgow who gave me the opportunities to play for a team who take immense pride in what it means to represent the Warriors, thank you.
“To the fans at Firhill and then Scotstoun who have given us incredible support over the years, without you our team wouldn’t be where it is today.
“To all my brothers, past and present, the memories I’ve made with you, on and off the pitch, will last a lifetime. I’ll miss the feeling after a game when you look around and know that everyone has given everything, although the not being sore part might be quite nice…
“Last of all, my long-suffering wife, Katie. Thank you for being there for the whole journey, for the many ups and down, for keeping me smiling and grounded along the way and for singlehandedly bringing up our kids whilst I was away doing what I loved.”
Only Rob Harley and Ryan Wilson have played more often for the Warriors than Fusaro, who made his Scotland debut in the 20-0 defeat by England in the 2014 Calcutta Cup match at Murrayfield.
He helped the national side defeat Italy in a nailbiting match in Rome a fortnight later and was part of the Scotland squad which toured the Americas in summer 2014, appearing as a replacement in the 21-19 win over Argentina in Cordoba. He won his final cap against South Africa in Port Elizabeth a week later.
Born in Kirkcaldy, Fusaro first came to prominence as part of the Bell Baxter High School team that won the Scottish Schools Cup in 2007. The side, which also included fellow Glasgow and Scotland player Pete Horne, was the last from a state school to win the trophy.
He came through the ranks at Howe of Fife, then played for Heriot’s before joining Glasgow. He was the club’s Player of the Season and Players’ Player of the Season in 2011-12.
Glasgow defence coach Kenny Murray paid tribute to Fusaro’s professionalism.
“Chris has been a player who not only gives everything on the pitch but is an example to others on how he prepares off it,” Murray said.
“The fact he has been a one-club player and sits third on the club’s all time appearance list is a testament to his team first attitude and commitment to Glasgow.
“He has been a fantastic servant to the club and is someone who will be missed in the environment.”